Crib safety

Hi moms my son will be 5 months in a few weeks and I’m thinking of starting him transition into the crib he’s definitely outgrowing his bassinet. I’m starting to get him comfortable being in the crib I leave him in there if I have to run to the bathroom etc he seems ok no more then 10min then he’ll fuss . I’ve notice most time he seems to be in his tummy and at times when he crying he puts his face directly down I worry if I leave him over night he will suffocate himself. There’s no pillow toys blankets he sleep in a sleep sack. Is this normal ?